On the action side ... say your character is armed with a sword and shield. Even though you have a basic block button, you tend to pull the directional stick away from opponents when you anticipate an attack. Doing this frequently in the context of combat causes your character to gradually move more quickly when stepping back, eventually developing a backward leap and increasing agility ... but failing to develop any skill at shield blocking, being easily staggered. Or perhaps you tend to strike out when you anticipate an attack, rather than use the block, and as a result your character parries more quickly, but still doesn't shield block so well. Or you use the block but tend to spam the attack button before the animation is over, eventually developing a shield bash. This is very simplified, but you get the idea. You would essentially grow your character, starting out untrained and slow and becoming something that handles crowds like Batman in Arkham City.
This was a damn fine idea, but the appeal of it was too similar to the Kinect wizardry game up there to use both, and I just can't resist the opportunity to slip in a Dragonlance joke -- for I am but a man, with all of man's weaknesses. But holy shit, what if you could do both? What if you could marry this idea of gradual, personalized skill-building with the motion control magic? What if that's how games like Skyrim or The Witcher work in the future? Choose to be a warrior, and you develop your skills in this fashion; choose to be a mage, and it's all gesture-operated spells. My God, that would be the end of nerds as a species. We would all die quietly, not with a bang, but with a nasally whimper, as we happily starved to death in front of our computers.
Herr Terror, what have you done?
Nobody's saying this is it, that these are the best possible game ideas in existence. They're just a few examples of all the vast untapped potential out there, literally just laying around in their frayed off-brand boxers and wasting their lives on Cracked articles. Think you have a better idea? Shit, you're probably right! Post it in the dang comments so that everybody here can experience the precise shade of blue your nerd balls have been, lo, these many years.
Fair warning, though: I am personally encouraging any and all game developers reading this right now to steal every single concept they see here. Dear Game Developers: I know you think you have a good idea for your next project, but you know what? Judging by the state of the game industry lately, you probably don't. Instead, if you have the talent and resources to take a crack at one of these, then for the love of God, steal from us. Do it shamelessly. Do it blatantly. Take every ounce of credit for everything but just give us the goddamn games already.
You can buy Robert's other book, Everything Is Going to Kill Everybody: The Terrifyingly Real Ways the World Wants You Dead, or follow him on Tumblr, Twitter and Facebook.